Exercise device



FIG. 1 is a front view of an exercise device showing a new design;

FIG. 2 is a perspective view of the base of the exercise device in FIG. 1; and,

FIG. 3 is a top perspective view of a top surface of the exercise device of FIG. 1.

The even broken lines showing a person and portions of an exercise device are environmental only and form no part of the claimed design. 

The ornamental design for an exercise device, as shown and described. 